STABLE AND QUASISTABLE SPATIO-TEMPORAL SOLITONS IN CUBIC QUINTIC NONLINEAR MEDIA

Abstract

The propagation and stability of spatio-temporal solitons (STSs) under the combined influence of dispersion, diffraction, self-focusing and self-phase modulation in a medium possessing cubic quictic nonlinearity is investigated. Using variational formalism, it has been shown that a pair of soliton state exists, of which, one is stable, while the other quasistable. It has been established that while the stable one is possible only in cubic quintic nonlinear (CQNL) media, the quasistable one is well known in Kerr media. Existence of these solitons is also verified by means of numerical experiment. Moreover, it is also shown that unlike bistable temporal solitons, no spatio-temporal bistable soliton exists in CQNL media. Dynamic behavior of solitons spatial and temporal widths which are different from that of the stationary soliton state is also investigated. Bound oscillatory and unbound regions are identified.